Patents by Inventor Robert W. Nottorf

Robert W. Nottorf has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Process for preparing a photographic emulsion containing tabular grains having narrow size distribution
    Patent number: 4722886
    Abstract: Process for preparing a photographic emulsion containing tabular silver halide grains which have narrow size distribution comprising:A. adding silver nitrate to a vessel containing dispersing medium/bromide mixture, initial bromide ion concentration is 0.08 to 0.25 N to form tabular seed grains;B. adding a basic silver halide solvent, e.g., ammonia, ammoniacal solution, etc. to achieve 0.02 N to 0.2 N of the solvent (e.g., after at least 2% by weight of total silver nitrate has been added);C. stopping silver nitrate addition for 0.5 to 60 minutes, e.g., bromide ion concentration is in the range of 0.005 to 0.05 N;D. neutralizing at least some of the basic silver halide solvent present; andE. adding additional silver nitrate and halide, i.e., Br.sup.- and BrI.sup.-, by balanced double jet procedure.The emulsions are used in photographic elements for x-ray, graphic arts, etc.
    Type: Grant
    Filed: October 10, 1986
    Date of Patent: February 2, 1988
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Robert W. Nottorf